Silent Stroke

Abstract

Background and Purpose— The prevalence of silent brain infarcts varies from 8% to 28% in the general elderly population. Silent brain infarcts are associated with increased risk of subsequent stroke and cognitive dysfunction. By definition, silent strokes lack clinically overt stroke-like symptoms and fail to come to clinical attention; however, impaired recall of symptoms may be a potential confounder. Our aim is to report a series of patients with incidentally detected acute and subacute strokes and examine whether they were truly asymptomatic. Methods— Subjects included in this study were drawn from ongoing dementia research studies at the Memory Ageing and Cognition Center, in which all participants underwent a cranial MRI. Incidental hyperintense lesions on diffusion-weighted imaging with corresponding apparent diffusion coefficient defects indicative of acute/subacute silent stroke were identified. Clinical data for individuals with incidental hyperintense lesions on diffusion-weighted imaging were collated. Results— Six of 649 subjects had incidental hyperintense lesions on diffusion-weighted imaging; on retrospective questioning, 3 recalled symptoms temporally correlated with MRI lesions, which had been reported to but ignored by family members. Two subjects had focal neurological signs. A majority of the subjects with incidental hyperintense lesions on diffusion-weighted imaging had significant cognitive impairment. Conclusions— A significant number of strokes may be “silent” due to lack of awareness of stroke-like symptoms in the elderly and their families. Enhanced stroke prevention education strategies are needed for the elderly population and, in particular, for their families.